1. Field of the Invention
The invention relates to a device for producing bound printed products, comprising at least one continuous folding device to which individual printed sheets are sequentially supplied and in which these sheets are individually folded; further comprising a gathering device in which the printed sheets folded in the continuous folding device are gathered astraddle to a pre-product; and a transport device receiving the pre-products from the gathering device. The gathering device comprises at least one blade which extends substantially parallel to the transport direction of the transport device and on which a certain number of printed sheets are gathered to form a pre-product.
2. Description of the Related Art
Devices of this kind are suitable particularly for so-called on-demand production in connection with digital printing machines. Digital printing machines enable a continuous change of the printed image without having to stop the printing machine. In this way, it is basically possible to sequentially produce books and other printed products with different contents and different page quantities without interruption. In this way, it is also possible to inexpensively produce small editions of books and other printed products. The storage costs can be kept at a minimum. Since it is possible to operate in-line without interruption, it is therefore also possible to keep the required manufacturing time at a minimum.
A device of the aforementioned kind is known in the prior art from the publication WO 01/34403 A2. With this device, the printed sheets which have been folded in a continuous folding device are gathered on two hubs provided with vanes. These two hubs provided with vanes are positioned in a single plane which extends transversely to the transport direction of the continuous folding device. They move relative to one another such that at one end of the continuous folding device a roof-shaped support is formed by two vanes on which the printed products are gathered to a pre-product. Once the predetermined number of printed sheets has been gathered on these two vanes, the two vane hubs are rotated in opposite direction and the roof-shaped support moves downwardly. The printed products are accordingly spread apart. When the spreading angle is substantially approximately 180 degrees, the pre-product is received by a driver of the transport chain and is supplied to a stitching machine. After stitching, the pre-products are cut or trimmed to size in a trimming machine. In this device it is disadvantageous that the two vane hubs require laterally a lot of space and that the pre-products upon placement onto the transport device are spread apart greatly and thus become unstable.
It is an object of the present invention to provide a device of the aforementioned kind which is more compact and has a higher output.
In accordance with the present invention, this is achieved in that means are provided with which the blade is movable in the transport direction.
In the device according to the invention, instead of the vane hubs a blade is used which requires significantly less space. The pre-products gathered on this blade are deposited substantially without spreading on the transport device. The placement without additional spreading can be carried out particularly advantageously by a linear movement of the blade. Once the pre-product is substantially completely removed or stripped off, it drops onto the transport device and is engaged by a driver of the transport device. The transport device must not be stopped, but it can be stopped for this purpose. Since the pre-products are not additionally spread apart, they are guided significantly more securely; this enables a higher speed and thus a higher output of the device.
According to a further embodiment of the invention, at least two substantially identical blades are provided on which sequentially a pre-product is gathered, respectively. Once on one of the blades a pre-product is completed, on the second blade a second pre-product can be gathered without interruption.
A particularly high production output is possible when, according to a further embodiment of the invention, the gathering device has a wheel-shaped carrier on which several blades are supported. Upon rotation of the wheel-shaped carrier, the blades move from the continuous folding device to the transport device. The blades move in one plane which extends vertically and parallel to the transport device. Such a carrier extends in the vertical direction and in the longitudinal direction but only insignificantly laterally so that a compact configuration is still possible. The blades of the wheel-shaped carrier are preferably embodied such that the have a passage at their upper edge, respectively. Upon rotation of the carrier, the blades can then pass substantially vertically a transport chain and deposit the pre-product thereon in this way. The supply of the printed sheets to the wheel-shaped carrier as well as the transport away from the carrier are realized, respectively, substantially radially relative to the wheel-shaped carrier. Each blade is preferably provided with a stop where the printed sheet or the pre-product is positioned. It is important that the pre-products upon deposition are not spread apart in this connection. The pre-products can thus be safely received by the drivers of the transport device.
According to another embodiment of the invention, two blades are provided, which are arranged at a spacing to one another above the transport device, and a deflecting switch is provided with which the printed sheets are supplied alternatingly to the two blades. The deflecting switch is preferably actuated or switched such that the pre-products are alternatingly gathered on the two blades. The two blades are preferably arranged directly above the transport device so that the pre-products can be transferred without spreading and with a short movement onto the transport device. Preferably, in this connection the blades are moved parallel to the transport direction and the pre-products are stripped off. After retraction of a blade, the corresponding pre-product is then immediately received by a driver of the transport device. Each blade has correlated therewith a continuous folding device. In principal, it is also possible to employ more than two blades, two continuous folding devices, and; accordingly, several deflecting switches. This embodiment enables a particularly high output while providing a compact configuration.
According to another embodiment of the invention, at least two blades are positioned above one another. These blades can be moved from a gathering position into a retracted waiting position. This provides a very compact arrangement with which it is also possible to gather alternatingly on these blades. For this purpose, the lower blade is, for example, in the gathering position while the upper blade is still in the retracted position. When the gathering process on the lower blade is finished, the upper blade moves into the gathering position above the lower blade and the lower blade transfers the pre-product onto the transport device. Subsequently, the lower blade moves back into the gathering position and receives the already gathered printed sheets from the upper blade in that the upper blade is retracted and the sheets are stripped off.
If desired, before transporting the pre-product away, a folded envelope can be added to the pre-product.
According to another embodiment of the invention, the pre-products are stitched and subsequently moved into a belt transport device. Clamped between the transport belts, the pre-products are stopped sequentially at a bottom knife and a top knife and trimmed or cut to size. The transport is controlled advantageously as a function of the size of the product. After the top trim has been carried out, the front trim or cut is performed by means of a third knife. The product, which is now finished, moves onto a delivery belt, for example, along a chute.